barcodefontsoft.com

Basic programming structure for image processing in .NET Generator Code 3 of 9 in .NET Basic programming structure for image processing

3.2 Basic programming structure for image processing use visual .net 3 of 9 generator toget barcode 39 with .net GS1 DataBar-14 Images may be thought of as t .net vs 2010 Code 3 of 9 wo-dimensional arrays. They are usually processed pixel-by-pixel in a raster scan.

In order to manipulate an image, two-nested for-loops is the most commonly used programming structure, as shown in Fig. 3.1.

. ...

...

. int row, col; ...

...

for ( ro .net framework Code 39 Extended w = 0; row < 128; row ++) { for( col = 0; col < 128; col++) { /* pixel processing */ ..

...

. } ..

...

. }. Fig. 3.1. Basic programming structure: two-nested for-loops. Writing programs to process images ...

...

. int row, col, frame; ...

...

f barcode 3 of 9 for .NET or (frame = 0; frame < 224; frame++) { for ( row = 0; row < 128; row++) { for( col = 0; col < 128; col++) { /* pixel processing */ ..

...

. } ..

...

. } }. Fig. 3.2. Basic programming structure: three-nested for-loops. In this example, we use two i Code 39 for .NET ntegers (row and col) as the indices to the row and column of the image. By increasing row and col with a step one, we are actually scanning the image pixel-wise from left to right, top to bottom.

If the image has more than two dimensions, (e.g. hyperspectral images) a third integer is then used as the index to the dimensions, and correspondingly, a threenested for-loops is needed, as shown in Fig.

3.2..

3.3 Good programming styles You should follow one importa visual .net Code 39 nt programming construct: all programs should be written so that they will work for any size image. You are not required to write your programs so that they will work for any number of dimensions (although that is possible too), or any data type; only size.

One implication of this requirement is that you cannot declare a static array, and copy all your data into that array (which novice programmers like to do). Instead, you must use the image access subroutines. Another important programming guideline is that except in rare instances, global variables are forbidden.

A global variable is a variable which is declared outside of a subroutine. Use of such globals is poor programming practice, and causes more bugs than anything else in all of programming. Good structured programming practice requires that everything a subroutine needs to know is included in its argument list.

Following these simple programming guidelines will allow you to write generalpurpose code easily and ef ciently, and with few bugs. As you become more skilled you can take advantage of the pointer manipulation capabilities to increase the run speed of your programs, if this is needed later..

3.4 Example programs for (<cond>) {. <body> } (a) the K&R style for (<cond>) { <body> } (b) the Allman style for (<cond>) { <body> } (c) the Whitesmiths style for (<cond>) { <body> } (d) the GNU style Fig. 3.3. The four commonly used indenting styles. You will lose major points if your code does not follow these guidelines. Besides the aforementioned pr ogramming guidelines, it is very important for students to also follow the indenting, spacing, and commenting rules in order to make your code readable. There are four commonly used indenting styles, the K&R style (or kernel style), Allman style (or BSD style), Whitesmiths style, and the GNU style, as shown in Fig. 3.

3. In this book, we use the Allman indenting style. Adding some space (e.

g. a blank line) between different segments of your code also improves readability. We emphasize the importance of the comments.

However, do not add too many comments since that will break the ow of your code. In general, you should add a block comment at the top of each function implementation, including descriptions of what the function does, who wrote this function, how to call this function, and what the function returns. You should also add a description for each variable declaration.

. 3.4 Example programs Take another look at the IFS manual. It will help you to follow these example programs. Also pay attention to the programming style we use.

The comments might be too detailed, but they are included for pedagogical purpose. A typical program is given in Fig. 3.

4, which is probably as simple an example program as one could write. Fig. 3.

5 lists another example which implements the same function as Fig. 3.4 does but is written in a more exible way such that it can handle images of different size.

Both these examples make use of the subroutine calls ifsigp, ifsipp, ifsfgp, and ifsfpp to access the images utilizing either integer-valued or oating point data. The advantage of these subroutines is convenience: No matter what data type the image is stored in, ifsigp will return an integer, and ifsfgp will return a oat. Internally, these subroutines determine precisely where the data is stored, access the data, and convert it.

All these operations, however, take computer time. For class projects, the authors strongly recommend using these subroutines. However, for production operations, IFS supports methods to access data directly using pointers, trading additional programmer time for shorter run times.

.
Copyright © barcodefontsoft.com . All rights reserved.